Scientists have created human embryos from slivers of skin – bringing closer the day when babies are cloned in the lab.

In experiments that mirror the cloning technique used to make Dolly the sheep, they took cells from men’s arms and legs and placed them into women’s eggs.

The embryos created lived for only five or six days, but they represent a key step in the quest for treatments for incurable diseases from Alzheimer’s to cancer.

Breakthrough: U.S. scientists have made a leap forward in stem cell research

Very early-stage embryos have been made from human skin before but the researchers claim to have got further than anyone else.

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Prof ROGER PEDERSON: 'The cloning procedure known as 'somatic cell nuclear transfer' (or SCNT), which had worked for Dolly the sheep and countless other species, did not result in cloned human stem cells — not for my lab ten years ago nor for any other lab that has tried it since then, until now. This new approach is a step towards overcoming immune rejection, a major obstacle to stem cell-based therapies.'

Importantly, according to the journal Nature, they appear to have worked out why others have failed – meaning the research could now progress in leaps and bounds. The scientists, from the New York Stem Cell Foundation Laboratory, paid 16 young women for their eggs and took tiny samples from the skin of two men.

They then placed the DNA from the skin cells inside the eggs and triggered them to grow and divide.

In the case of Dolly, the eggs used were ‘hollowed-out’ – their DNA had been removed.

But here, the technique only worked properly when the eggs’ DNA was left in, showing there is something about it that is vital for the creation of life.

The extra genes in the embryos mean they do not, strictly speaking, qualify as clones.

But Josephine Quintavalle, of campaign group Comment on Reproductive Ethics, said: ‘Cloning is cloning however it is achieved. If women stopped selling their eggs, we could close down this unethical dead-end research once and for all.’

In Britain, embryos can be cloned for research purposes but must be destroyed after 14 days and cannot be implanted into a woman.

Robert Lovell-Badge, a stem cell expert at the National Institute for Medical Research in London, stressed scientists are still a long way from being able to clone a baby.

He added: ‘No respectable scientist or clinician has the intention of cloning people. In fact, there really isn’t any reason to do it.’